Pseudo-hydrothorax in peripheral venous catheterization in an extremely premature neonate--case report

The authors describe very rare complication (pseudopleural effusion) after peripheral venous cannulation (Introcan-W 24G3/4 through v. axilaris) in extremely premature newborn with birth weight 600 grams, which lead to worsening of patient's respiratory insufficiency. Ultrasonographic examination confirmed extrapleural process without necessity of surgical intervention. Cannula extraction and infusion interruption were followed by spontaneous regression of the complication, thereafter artificial ventilation was discontinued and baby was discharged.     

Parenteral nutrition and nitrogen balances in low birth weight newborns in the adaptation period (author's transl)]

Nitrogen balance studies were performed in the course of parenteral nutrition in the first 5 days of life in three groups of low birth weight newborns (I. group = 12 premature, 27.--30. gestational week, b. w. M = 1298 g, II. group = a) 7 prematures, 27.--31.g.w.,b.w.M = 1295 g,b) 5 small for date prematures, 29.--32.g.w.,b.w.M = 1208 g, III. group = 10 prematures, 31.--36.g.w.,b.w. M = 1751 g). Losses of nitrogen via urine in extreme prematures during the adaptation period are higher than in full term or moderate prematures. Increased volume of parenteral nutrition (glucose, fat emulsion) and increased caloric quotient did not produce a significant restriction of N-losses via urine. No difference was found in N-losses between extreme prematures and small for date prematures of similar birth weight/group IIa): IIb)/. Aminoacids (cca 500 mg N/kg body weight/24 hrs) given on the second day of life were well retained; increased losses of N represented about 20% of N infused.     

Nitrogen balances in very premature newborns in the course of parenteral nutrition (author's transl)]

Nitrogen balance studies were performed in the course of parenteral nutrition during the first 5 days of life in 2 groups of premature newborns (I. group: 7 prematures, b.w. M = 1295g; II. group: 7 prematures, b.w. M = 1447g). Glucose and fat emulsion were administered intravenously in children of the first group, in the second one L- Aminoacids (250 mg N/kg body weight/24 hrs.) were added. In comparison with the first group nitrogen retention of 77 to 170 mg/kg body weight/24 hrs. was reached, but blood urea concentration increased significantly.     

Desipramine binding to noradrenaline reuptake sites in cardiac sympathetic neurons in man in vivo

Noradrenergic reuptake blockade is a recognised mechanism of antidepressant action, but the extent of the blockade necessary for therapeutic effect is not known and plasma levels do not provide a guide to therapy. We report a method to assess noradrenaline reuptake blockade in vivo in man using [11C]meta-hydroxyephedrine and the multiple organs' coincidences counter. Eight healthy volunteers had two scans, one with tracer alone and one after preloading with desipramine 50-75 mg p.o. In all subjects, there was an increased washout rate of the radioligand from the heart following preloading (t=4.38; P<0.003) as well as a decrease of the area under the [11C]meta-hydroxyephedrine time activity curve (t=7. 4; P=0.001). In one subject who had three doses of desipramine, the increase in washout rate was dose-dependent. In conclusion, [11C]meta-hydroxyephedrine in the multiple organs' coincidences counter gives a valid, low radiation method to assess noradrenergic reuptake blockade in the clinic.     

Guided tissue regeneration, barrier membranes and reconstruction of the cleft maxillary alveolus

The use of barrier membranes for bone regeneration is especially beneficial in the case of severely affected soft tissue. One useful indication may be the formation of an effective shell for bone grafts in maxilla cleft defect reconstruction. When selecting a proper material for clinical use, one must consider the safety record, the resorption time and route of elimination, the time of the maintained barrier function, the necessary time of mechanical strength, and costs. Two resorbable collagen membranes, one of single-layer and one of double-layer material, were tested in vitro and in vivo. The tested single-layer membrane is less expensive, but it is also less handling than the double-layer membrane. In vitro, samples were incubated in simulated surgical wound. A complete unambiguous picture of disintegration was not proved histologically in either material in six investigation terms (1-6 weeks). In vivo the effect of the assessed membranes was verified on a group of patients (N = 45) with a cleft. Materials were applied in the reconstruction of the alveolar defect by cancellous bone grafts. The influence on the course of healing was not stated as statistically significant. However, with respect to the costs of double layer membrane, this material was used in the most severe cases.     

Evaluation of [O-methyl-11C]RS-15385-197 as a positron emission tomography radioligand for central alpha2-adrenoceptors

Carbon-11 labelled RS-15385-197 and its ethylsulphonyl analogue, RS-79948-197, were evaluated in rats as potential radioligands to image central alpha2-adrenoceptors in vivo. The biodistributions of both compounds were comparable with that obtained in an earlier study using tritiated RS-79948-197 and were consistent with the known localisation of alpha2-adrenoceptors. The maximal signals (total to non-specific binding) were, however, reduced, in the order [11C]RS-79948-197 < [11C]RS-15385-197 < [3H]RS-79948-197, primarily due to the difference in radiolabel position (O-methyl for carbon- 11 compared with S-ethyl for tritium). This resulted in the in-growth of radiolabelled metabolites in plasma, which, in turn, contributed to the non-specific component of brain radioactivity. Nonetheless, the signal ratio of approximately 5 for a receptor-dense tissue compared with the receptor-sparse cerebellum, at 90-120 min after radioligand injection, encouraged the development of [O-methyl-11C]RS-15385-197 for human positron emission tomography (PET). Unfortunately, in two human PET scans (each of 90 min), brain extraction of the radioligand was minimal, with volumes of distribution more than an order of magnitude lower than that measured in rats. Following intravenous injection, radioactivity was retained in plasma and metabolism of the radiolabelled compound was very low. Retrospective measurements of in vitro plasma protein binding and in vivo brain uptake index (BUI) in rats demonstrated a higher protein binding of the radioligand in human compared with rat plasma and a lower BUI in the presence of human plasma. It is feasible that a higher affinity of RS-15385-197 for human plasma protein compared with receptor limited the transport of the radioligand. Although one of the PET scans showed a slight heterogeneity in biodistribution of radioactivity which was consistent with the known localisation of alpha2-adrenoceptors in human brain, it was concluded that [O-methyl-11C]RS-15385-197 showed little promise for routine quantification of alpha2-adrenoceptors in man.     

A new human (psycho)pharmacology tool: the multiple organs coincidences counter (MOCC)

We describe a novel instrument which is capable of measuring the uptake of radioligand in human organs in vivo with the administration of very small doses of positron-emitting radioligands. This technique readily detects the displacement or reduced uptake of radioligand when a competitive agonist or antagonist is administered. This system provides no tomographic information, but the small radioactive doses involved mean that investigations can be repeated at regular intervals and that female volunteers can also participate. We administered [(11) C]flumazenil, [(11)C]diprenorphine, [(11)C]meta -hydroxyephedrine (MHED) and [(11)C]RTI 55 to healthy male volunteers and performed control, pre-loading and displacement experiments. These demonstrate the feasibility of using this technique to investigate benzodiazepine and opiate receptor occupancy, as well as occupancy at dopamine, noradrenaline and serotonin (5-HT) re-uptake sites. This method is likely to be useful in pharmacokinetic/pharmacodynamic experiments, in drug development and discovery and in the development of novel imaging radioligands.